Among various flat panel display devices, thin film transistor liquid crystal displays (TFT-LCD) dominate the mainstream flat penal display market due to their compact size, low power consumption, relatively low manufacturing cost, and zero radiation. A liquid crystal display device mainly includes a liquid crystal display panel and a back light module. The back light module is the light source that provides the light to illuminate the liquid crystal display panel. The light emitted out of the liquid crystal display panel is modulated by the liquid crystal display panel to display images.
FIG. 1 illustrates a schematic view of a liquid crystal display panel. Referring to FIG. 1, a liquid crystal display panel includes a liquid crystal cell 100 and two polarizers 101 and 102 attached to the upper and lower sides of the liquid crystal cell 100. The liquid crystal cell 100 includes a color filter. The light emitted from the back light module passes through the color filter and is mixed together to display various colors. Ideally, the displayed colors reproduce the natural colors as much as possible. Alternatively, the displayed colors are adjusted to approximate the desired colors to satisfy user's requirements and to adapt to the specific application environment of the liquid crystal display panel.
The white point adjustment is among most important aspects of color adjustment. FIG. 2 illustrates a schematic view of a CIE-xy chromaticity diagram. Referring to FIG. 2, the diagram represents a given color in chromaticity hue and saturation position in the color base coordinate system. Specifically, the XYZ display system has the tristimulus values X, Y, and Z represented in the chromaticity coordinates as the horizontal axis x=X÷(X+Y+Z) and the vertical axis y=Y÷(X+Y+Z). All the colors that can be seen by human eyes are shown in the diagram as the inner portion of the horseshoe shape formed by the closed curve C. The R, G, and B points in the diagram represent the three primary colors, red, green, and blue respectively in a certain color display system. All the colors on the sides of the triangle RGB or inside the triangle RGB may be represented in a proper mixture of the three primary colors. In addition, the white color with the maximum brightness is represented at the point W where all three primary colors reach the maximum brightness. The white color W point is in the vicinity of the triangle RGB centroid.
When designing a color display system, an optimized and requirement satisfying white color point is obtained by adjusting the maximum brightness of the R, G, and B points. In the current technologies, the thicknesses of the red color barriers, green color barriers, and blue color barriers in the color filter are adjusted to optimize the white color point. For example, increasing the thickness of the green color barriers may decrease the light-transmittance of the green color barriers and thereby reduce the maximum brightness of the green light.
However, the method of matching the white color point by adjusting the thicknesses of the color barriers may have certain limitations. For example, after the thicknesses of the color barriers are determined, the brightness of the color barriers cannot be changed. When the color display system has additional special requirement for the white color point, further adjustment of the thicknesses of the color barriers to optimize the white color point may cause substantial differences in the thicknesses of the color barriers and thereby may affect the display effect.
Another drawback of the color barrier thickness adjustment method is that each white color point designed for a certain specification requires a matching color filter with fixed thicknesses of the color barriers. As a result, liquid crystal display panels with different product specifications may need different color filters. The inability of sharing a common color filter across different liquid crystal display panel products may increase the production cost.
The disclosed liquid crystal display panel and fabrication method are directed to solve one or more problems in the art.